Infinite Slabs – The Bryce-killers

Infinite Slabs – The Bryce-killers

You have a fairly decent computer, with a 3GHz CPU and you have plenty of RAM – 2Gb, and you would like a plane of fluffy looking clouds in a Bryce scene, but you don’t want the two dimensional stuff that Bryce tends to produce ad nauseum. Solution – according to the Bryce manual is an infinite slab. Essentially an infinite slab is a plane object that has depth. An Infinite Slab can affect objects within it. Anything you place within the slab’s depth will be affected by the slab’s volume color.

Infinite Slabs are usually used to create water but are also suggested for creating 3D clouds, but when you make use of volumetrics in an infinite slab it will kill Bryce. A render that took a couple of minutes without the slab will now take hours and you will suffer the "hospital waiting room blues".

You lovely powerful computer doesn’t amount to much and tweaking materials and lighting to get the look you want will be virtually impossible as you will have to wait hours before you can see if your minor tweak has the desired effect.

I rediscovered a method I used for my "Ocean Gypsy" image, using stacked cloud planes to give the impression of 3D clouds, and have refined it a little bit more. It will certainly cut down on your render time and as you will see is quite acceptable visually.

To compare the speed differences I created a scene Bryce and applied the "Bryce Shortcut #2" under the Daytime library. Select SkyLab preset

I then created an infinite slab. (by holding down the left mouse button when selecting the Cloud plane creation gadget and selecting the "Volume" option.)Select Volume option

I applied a volumetric preset I had in my library called "Cloud Puffy Frac Stone", which I thought would give me a good puffy cloud.Select a volumetric preset

A quick glance at the Material settings showed me that this was not "Bryce-killer" as the quality settings in most cases were not set too high.Not too CPU-intensive

Back to the main Bryce Editor window told me a different story. The nano-Preview rendered very slowly and I could see already that I was in for a long wait. So I hit the Render button and went to bed!

The following morning the following results told their own story – a 4 hour 45 minute render!Slow Render

Back to the drawing board! This time I created the same scene with the same sky preset and selected a infinite cloud plane this time. Cloud Plane

I chose the "Cotton Ball Storm" Clouds-Surface Preset in the Atmospherics library of Bryce 6.1. It seemed a bit dark and flat so I tweaked the material settings in the Material editor raising the Ambient and Specular settings:Preset Library

...and my tweaks...

Still nothing spectacular…yet…but now comes the fun part.

Selecting the cloud plane I pressed Shift-Alt-D (Multi-Replicate) and set the requester to 10 copies offset on the Y axis by 0.2 Bryce units.Multi-Replicate

Immediately the nano-Preview updated a lot faster and the results looked good, but the proof of the pudding is in the eating…so I pressed the Render button.Turboboost!

As you can see the render is a lot quicker. 3 minutes compared to over 4 hours. The results are similar and with a little bit of tweaking in the Material Editor, very similar results can be obtained at a fraction of the rendering time!

Keep on Brycin’

Infinite Slabs – The Bryce-killers

When doing clouds – think big!

ArtifactsFree-standing clouds in Bryce have never worked to me – until recently. I discovered a glaring fact when watching the shadows cast by the clouds on a wheat field in the Caledon district. The cloud didn’t look particularly big but the shadow must have been at least a kilometre across. I realised that a cloud is a big thing.

My clouds in Bryce were simply too small so the cloud material (set to Fuzzy Shade mode) just lacked the minute detail and scale that a normal fluffy cloud would have. I normally create clouds with squashed spheres and apply a simple cloud material to it – volumetric clouds just kill the rendering time, and the dreaded intersection artefacts when two volumetric objects intersect (the image thumbnail enlarges to show what I mean), make the exercise more frustrating than rewarding. This time I cranked up the size and made the cloud colossal (in comparison to the terrain) and it actually started to work. My advice to you – think big! :idea: